Why are text objects not mesh objects?
It has to do with specific font properties.
And also copyright rights :).


Modern computer fonts don't have fixed proportions like meshes do.
They're ever so slightly adjusted when you scale them up/down, to look optically correct.  
In low resolutions, they also take advantage of hinting data, to avoid pixel distortion.
Good fonts also contain kerning data. This tells them how much space to put between different character pairs. And allows for ligatures.


When you convert text to mesh/rasterize it, it loses all of these important features.
That's why some font creators explicitly prohibit rasterizing.



Font characters slightly change when scaled, to keep their legibility


Ligature - joining two glyphs into one. Not possible to execute with rasterized text.